Category Archives: High Altitude

Exostosis of the External Auditory Canal – Surfer’s Ear

You do not have to be a surfer to have surfer’s ear, but what is it exactly?

Not to be confused with swimmer’s ear surfer’s ear or exostosis of the ear auditory canal is when there is the presence of multiple benign boney outgrowths. It is quite common in individuals who have repeated exposure to cold water or wind, which typically ends up being those who surf waves in the pacific.

So now that we know what surfer’s ear is, how can we tell if we have it?

The diagnosis of Surfer’s ear is made by visual exam with an otoscope by a medical provider. Generally, there are no symptoms of Surfer’s ear unless there are multiple bony outgrowths, or the ones present are occluding your ear canal. In those cases, you may experience ear infections as these outgrowths can narrow the ear canal causing water and debris to become trapped and cause an infection. When there is significant occlusion of the ear canal typically 90% or more conductive hearing loss may occur.

What is the treatment for surfer’s ear?

A great preventative tool, to decrease the occurrence of these bony outgrowths is to wear ear protection like ear plugs when you have exposure to cold water or earmuffs when exposed to cold winds. As mentioned above, when there is only a few and/or small boney outgrowths there tends to be no associated symptoms and in those cases no need for treatment. In those, however, that continue to have exposure to cold water/winds, have several boney outgrowths and/or significant occlusion the only definitive treatment is to have those bony outgrowths removed surgically, this is typically done by an Ear, Nose, and Throat specialist.

References

  1. Surfer’s ear. UCI Health Otolaryngology. https://www.ucihealth.org/medical-services/ear-nose-throat-ent/hearing-ear-disorders/surfers-ear. Accessed October 11, 2022.
  2. Weber PC. Etiology of Hearing Loss in Adults. UpToDate. https://www.uptodate.com/contents/etiology-of-hearing-loss-in-adults?search=surfers+ear§ionRank=1&usage_type=default&anchor=H9&source=machineLearning&selectedTitle=1~150&display_rank=1#H9. Published March 15, 2022. Accessed October 11, 2022.
A young woman with chest-length, curly, dark brown hair smiles showing bright white teeth, dressed in a white coat over a black top.

Gabriela Rodriguez Ortega is a second year Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up in South Florida and received a Bachelor of Science in Biomedical Sciences and Bachelor of Arts in Psychology from the University of South Florida (Go Bulls!). Prior to PA school, she held many positions in the medical field including ENT medical assistant/scribe, pharmacy technician and ER medical scribe. In her free time, she enjoys spending time with family and friends, running, hiking, roller skating and playing guitar.   

Altitude Promotes Better Survival Rates in Critically Ill Obese Patients with COVID-19: A Presentation from the Chronic Hypoxia Symposium

The 8th Chronic Hypoxia Symposium is recently took place in La Paz, Boliva, and I had to pleasure of hearing Dr. Jorge Luis Velez’ presentation on altitude, obesity, and COVID-19 survival rates. Dr. Velez is an intensive care doctor and the head of critical medicine at Pablo Arturo Suarez Hospital in Quito, Ecuador, as well as being a professor at the Central University of Ecuador. With Quito being the second highest in elevation capital in the world at 9,350 feet, Dr. Velez understands the effects of altitude on the human body.

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Dr. Velez conducted a study among 340 unvaccinated adult patients with severe COVID-19 infections requiring intubation. Of the 340 patients, 45% were obese, 43% were overweight, and 12% were of normal weight. The results of the study showed that obese patients had significantly reduced mortality rates and higher rates of successful extubation when compared to the overweight and normal weight groups. Successful extubation is commonly described as extubation without the need for re-intubation within 72 hours. Obese patients were found to have a 31.17% mortality rate and an 81.03% rate of successful extubation. Overweight patients were found to have a 40.14% mortality rate and a 73.00% rate of successful extubation. Patients of normal weight were found to have a 48.72% mortality rate and a 53.85% rate of successful extubation.

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These results are surprising given that obesity is a widely accepted risk factor for high severity COVID-19 infections and increased mortality. Other factors that may have contributed to the increased survival rates of obese patients with severe COVID-19 infections is that in their study, the obese patients happened to be on average younger and a higher proportion of males. Despite variables in age and sex, Dr. Velez still concludes with statistical significance that “patients with obesity had a 52% less probability of dying in relation to those of normal weight.”

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Despite this emerging research, we still recommend maintenance of a healthy weight and lifestyle, as the effects of a healthy weight have been extensively researched and proven to be beneficial for a heart health, joint health, mental health, sleep, the digestive system, and more.

Family Nurse Practitioner Ana Sofia Bedoya administering the new bivalent COVID-19 vaccine to Dr. Chris in her office at Ebert Family Clinic in Frisco, CO.

Looking for other ways to protect yourself from COVID-19?

The new bivalent vaccine uses the same technology with upgraded protection against the omicron variant. The vaccine is the best way to reduce risk for you and your family during the holiday season, as well as protecting from reinfection if you’ve already had COVID-19.

References

Luis Velez, J., 2022. Altitude Promotes Better Survival Rates in Critically Ill Obese Patients with COVID-19.

Artime, C. A. A., & Hagberg, C. A. H. (2014, June). Tracheal Extubation. Respiratory Care, 59(6), 991–1005. https://rc.rcjournal.com/content/respcare/59/6/991.full.pdf#:~:text=Successful%20extubation%20is%20dependent%20on%20two%20factors%3A%20the,a%20planned%20extubation8%3B%20however%2C%20this%20definition%20does%20not

Cameron Santiago is a second-year Physician Assistant Student at Red Rocks Community College in Arvada, CO. He grew up in Colorado Springs and received his undergraduate degree in Biology from Colorado State University. Prior to PA school, he was an inpatient phlebotomist and urgent care technician. In his free time, he enjoys fishing, hiking, and spending time with his dogs and family.

HARPE is the New HAPE

It took ten years for me to convince high altitude experts that children living in the mountains get high altitude pulmonary edema (HAPE) without leaving home. My observations were published in 2017 in the Journal of High Altitude Medicine and Biology,

High-Altitude Pulmonary Edema
in Mountain Community Residents

This week Dr. Jose A Castro-Rodriguez MD PhD ATSF discussed HAPE in children at the 8th World Hypoxia conference in La Paz including the now renamed high altitude resident pulmonary edema (HARPE) in his presentation.

Dr. Castro-Rodriguez emphasized the importance of recognizing the three forms of HAPE, including reentry HAPE when children return to the mountains from vacation, since these can be life threatening.

My work has been cited in articles by pulmonologists Deborah Liptzin and Dunbar Ivy from Children’s Hospital of Colorado and geneticist Christine Eichstaedt and her team at the University of Heidelberg.

At Ebert Family Clinic we give every patient/family a free pulse oximeter. The ability to measure the oxygen saturation of anyone with cough, congestion, or fatigue can facilitate early treatment with oxygen and prevent visits to the emergency room, hospital and intensive care unit.

I recently received first prize for a poster presentation on HARPE at the fall Colorado Medical Society meeting, and second prize for a poster on Trauma and HAPE.

For more information about HAPE, HARPE and Trauma-related HAPE, see previous blog entries.

References

Ebert-Santos C. High-Altitude Pulmonary Edema in Mountain Community Residents. High Alt Med Biol. 2017 Sep;18(3):278-284. doi: 10.1089/ham.2016.0100. Epub 2017 Aug 28. PMID: 28846035.

Giesenhagen AM, Ivy DD, Brinton JT, Meier MR, Weinman JP, Liptzin DR. High Altitude Pulmonary Edema in Children: A Single Referral Center Evaluation. J Pediatr. 2019 Jul;210:106-111. doi: 10.1016/j.jpeds.2019.02.028. Epub 2019 Apr 17. PMID: 31005280; PMCID: PMC6592742.

Liptzin DR, Abman SH, Giesenhagen A, Ivy DD. An Approach to Children with Pulmonary Edema at High Altitude. High Alt Med Biol. 2018 Mar;19(1):91-98. doi: 10.1089/ham.2017.0096. Epub 2018 Feb 22. PMID: 29470103; PMCID: PMC5905943.

Eichstaedt CA, Mairbäurl H, Song J, Benjamin N, Fischer C, Dehnert C, Schommer K, Berger MM, Bärtsch P, Grünig E, Hinderhofer K. Genetic Predisposition to High-Altitude Pulmonary Edema. High Alt Med Biol. 2020 Mar;21(1):28-36. doi: 10.1089/ham.2019.0083. Epub 2020 Jan 23. PMID: 31976756.

High-Altitude Pulmonary Edema is not just for tourists

HAPE can affect long term locals too. There is no specific test to diagnosis HAPE leading to delayed treatment or improper treatment, including death.

HAPE is defined as fluid accumulation in the lungs when an individual spends about 48 hours at elevations of 8,200 feet or higher. This can occur when 1) tourists who are not accumulated to high altitudes appropriately 2) locals who re-enter high altitude after being at lower elevation for a period of time or 3) long term residents who develop an illness.

What are the signs and symptoms you ask? Exhaustion, dyspnea on exertion, productive cough, tachypnea, tachycardia, low oxygen saturation levels, and crackles upon lung assessments are the most common to be seen. These are very generic symptoms and resemble many other diseases, such as pneumonia and asthma, leading to misdiagnosis and improper treatment.

How is HAPE treated?

The answer is simple, oxygen. The body is being deprived of oxygen and is unable to feed our cells. By giving oxygen (either through an artificial source or returning to lower elevation) and allowing the body to rest, the body is able to meet its demand for oxygen and symptoms resolve. If one receives oxygen and symptoms do not improve, there is most likely an underlying cause that is contributing to the symptoms unrelated to HAPE.

A pulse oximeter is the easiest way that one can monitor their oxygen levels at home. This device can be purchased over the counter, relatively inexpensive, and easy to use. By placing the pulse oximeter on one’s finger, the device will read the individual’s oxygen level which should be greater than 90% (when at altitude). The heart rate will also be recorded which tends to be between 60-100 beats per minute when at rest for adults.

References

A new mechanism to prevent pulmonary edema in severe infections. Lung Disease News. (n.d.). Retrieved September 2, 2022, from https://lungdiseasenews.com/2015/01/14/researchers-discover-a-new-mechanism-to-prevent-pulmonary-edema-in-severe-infections/

Bhattarai, A., Acharya, S., Yadav, J. K., & Wilkes, M. (2019). Delayed-onset high altitude pulmonary edema: A case report. Wilderness & Environmental Medicine, 30(1), 90–92. https://doi.org/10.1016/j.wem.2018.11.002

Fixler, K. (2017, October 12). Colorado doctor: Health effects of living in mountains unknown to medical establishment. SummitDaily.com. Retrieved September 2, 2022, from https://www.summitdaily.com/news/summit-county-doctor-makes-a-case-for-high-altitude-disorder-that-affects-even-the-acclimated/

Interview with Retired Fighter Pilot Andrew Breithaupt: Altitude Earth and Sky

I had the honor of interviewing Andrew Breithaupt who recently retired from US Customs and Border Protection in the Department of Homeland Security where he served as an Air Interdiction Agent piloting multiple types of aircraft.  He currently serves as a Lieutenant Colonel on active duty for the US Army, stationed in Minneapolis, MN.  He began Army flight school in 1992 to become a helicopter pilot, ultimately qualifying in 4 different types of Army helicopters including the UH-1H, OH-58, AH-1, and the AH-64 Apache for which he became an Instructor Pilot training new Army aviators at Fort Rucker, Alabama.  Later he began his transition to fixed-wing aircraft in the civilian community. After nearly 10 years of Army active duty and multiple overseas tours, he was selected to enter service for US Customs and Border Protection where he served as a federal law enforcement agent for over 20 years, retired in December of 2021.  He holds his commercial pilot license for single engine & multi-engine fixed wing as well as rotorcraft with instrument privileges and aircraft type ratings. He has over 30 years of aviation experience and more than 2,500 hours of flight time over his career. I sat down to chat with him about his accomplished career and learn more about his aviation and altitude expertise.

In army flight school, specifically aeromedical training, he was taught the effects of aviation on the body. One of the first lessons they learned in their training was how to recognize the early warning signs of hypoxia. These include shortness of breath, dysphoria, nausea, vomiting and lightheadedness. This type of training is often done in altitude chambers, so trainees can experience these effects before they are in the air, including how aviation can affect your vestibular senses. A position change as simple as looking down to change a radio or instrument can completely disorient a pilot due to the change in direction of the fluid within the inner ear against the cilia. This can lead to the sensation that the plane has rotated and flying sideways. They are taught to trust their instruments because an overcorrection can lead to what they teach in flight school as a “death spiral.” The training is often done in a Barany Chair and simulates vestibular senses experienced during flight.

Elevation in Summit County, Colorado ranges from 7,947 feet to 14,270 feet, the highest peak being Gray’s Peak. With people living as high as 11,200 feet, as Andrew does at his home in Blue River located south of of Breckenridge, CO.  Andrew shared some very interesting aviation altitude requirements which might surprise some. He spent much of his career operating non-pressurized helicopters and Federal Aviation Regulations prohibited him from going between 10,000 feet to 12,000 feet for more than 30 minutes without oxygen. When flying above 12,000 feet, pilots are required to have supplemental oxygen regardless of the amount of time spent at that elevation depending on the category of aviation being conducted such as commercial operations. This is according to the CFR (Code of Federal Regulations) Part 135 which governs commercial aircraft operations. How interesting is it that pilots have these regulations, yet many people who live in Summit County or those summiting 14ers (peaks at 14,000 ft. or above) are at or above these elevations with no supplemental oxygen on a daily basis. When flying private aircraft, CFR part 91.211 specifies flight crew can fly without pressurization or supplemental O2 below 14,000 feet and passengers below 15,000 feet.

While in the Army, Andrew would rarely operate aircraft above 8,000 feet and would typically not have supplemental oxygen on board. They were trained to begin descent immediately if they were to notice the early signs of hypoxia. Keeping a pilot’s license requires strict annual or even semi-annual FAA physicals and continued training to ensure their bodies can withstand the effects of aviation.  As you can imagine those holding these licenses are some of the most fit men and women in the country.  Andrew rarely felt the effects of altitude even with altitude changes as great as 8,000 feet coming from sea level. He would typically remain at these elevations for two hours or less piloting non-pressurized aircraft.

To give some perspective, when you hop on a commercial flight for your next adventure these planes typically fly around 28,000 to 36,000 feet of elevation. When beginning the ascent, the aircraft pressure stabilizes at 6,000 to 8,000 feet, approximately when the dreaded “popping of the ears” is felt. Supplemental oxygen and quick donning masks are required on all these aircraft in case depressurization were to occur due to the rapid hypoxia which would occur at such high altitudes.

Andrew moved to Summit County in November of 2021 from Stafford, VA with his wife and five sons ages 24, 22, 19, 14, and 11.  Andrew and his family spent a significant amount of time in Summit County for snowboarding and skiing competitions and quickly fell in love with the area prior to spending the last 5 years living in Stuttgart, Germany. This is when they decided one day, they would become full-time residents of the county. They moved here for the “people, climate and lifestyle,” a combination I am learning is hard to beat outside of Summit County. With ski and snowboard season right around the corner, he and his family are excited to get back out on the slopes.   Andrew currently travels between his home in Blue River and Minneapolis for his position in the Army. With each trip back he feels his body more quickly adjust to the altitude changes. Thank you for your service Andrew, and welcome to the community!

Ellie Martini grew up in Richmond, VA and is currently a second-year Physician Assistant student at Drexel University in Philadelphia, PA. She completed her undergraduate degree at The College of William and Mary in Williamsburg, VA where she received her BS in Biology. Before PA school she worked as a rehab tech and medical scribe at an addiction clinic. In her free time she enjoys hiking, biking, group fitness, traveling and spending time with friends and family. 

Lost, Stranded, and Hungry in the Mountains of Western Colorado? A Mini Guide to Edible Plants

From backpacking and camping to skiing and snowboarding, there are plenty of activities outdoors in the Colorado high country. If you find yourself wandering around and lost without food in the mountains, there are several wild plants that you can eat. 

However, before you consume the delectable greens, there are a few precautions to take.

Moose shopping
  • Do not eat any wild plants unless you can positively identify them. There are iOS and Android apps that you can download prior to your hike to help distinguish plants, such as PictureThis and NatureID. 
  • Be aware of environmental factors such as pollution or animal waste. Avoid popular wild animal gathering areas.
  • Make sure you’re not allergic to the plant by rubbing it against your skin and observing for a reaction. If so, do not eat the plant. Before ingesting a large quantity, eat a small amount and check for a reaction. 

It may be difficult to cook if you did not come prepared with a portable stove, pots, and water, which could limit ways to enjoy vegetation. Here is a list of edible plants, how to identify them, where can they be found, and which part you can eat.

Wild plants

Dandelions (Taraxacum officinale): yellow ray florets that spread outward from center with toothy, deep-notched, hairless basal leaves and hollow stems. They can be found everywhere and anywhere. Every part of the dandelion plant is edible including the leaves and roots.

Yellow-green hemispheres bud in a bunch from green stems with pine needle-like leaves.

Pineapple Weed/ Wild Chamomile (Matricaria discoidea): the flower heads are cone-shaped and yellowish-green and do not have petals. Often found near walking paths and roadsides, harvest away from disturbed, polluted areas. If you’re feeling anxious about being lost, pineapple weed promotes  relaxation and sleep and serves as a  digestive aid.

Fireweed (Epilobium angustifolium): vibrant fuchsia flowers. Grows in disturbed areas and near recent burn zones. Eat the leaves when they are young as  adult leaves can stupefy you. Young shoot tips and roots are also edible. 

Wild onions (Allium cernuum): look for pink, lavender to white flowers with a strong scent of onion. They grow in the subalpine terrain and are found on moist hillsides and meadows. Caution: do not confuse with death camas. If it doesn’t smell like an onion and has pink flowers, it is not likely an onion.

Cattails (Typha latifolia or Typha angustifolia): typically 5-10 feet tall. Mature flower stalks resemble the tail of a cat. Grow by creek, river, ponds, and lakes. This whole plant is edible, from the top to the roots. Select from pollution-free areas as it is known to absorb toxins in the surrounding water.

Wild berries:

Wild strawberries (Fragaria virginiana): they are tiny compared to  store-bought. Can be identified by their blue-green leaves; small cluster of white flowers with a yellow center; and slightly hairy, long and slender red stems.

Huckleberries (Vaccinium spp): They grow in the high mountain acidic soil and flourish in the forest grounds underneath small, oval-shaped, pointed leaves. They resemble blueberries and have a distinguishable “crown” structure at the bottom of the berry. They can be red, maroon, dark blue, powder-blue, or purple-blue to almost black, and they range from translucent to opaque.

Deep blue berries stand out against bright red and green, waxy leaves.

Oregon grapes (Mahonia aquifolium): powder-blue berries, resembling juniper berries or blueberries, with spiny leaves similar to hollies that may have reddish tints.

Fun fact: The roots and bark of the plant contain a compound called berberine. Berberine has antimicrobial, antiviral, antifungal, and antibiotic properties.

Mushrooms

Brown whole and halved mushrooms lie on a green table with ridged, sponge-looking caps.

True morels (Morchella spp.): cone-shaped top with lots of deep crevices resembling a sponge. They will be hollow inside. A false morel will have a similar appearance on the outside but will not be hollow on the inside and are toxic. Morels are commonly found at the edge of forested areas where ash, aspen, elm, and oak trees live. Dead trees (forest wildfires) and old apple orchards are prime spots for morels.

Short, stubby mushrooms with white stems and brown camps stand in a row growing over grass.

Porcini (Boletus edulis): brown-capped mushrooms with thick, white stalks. Found at  high elevations of 10,500 and 11,200 ft in  areas with monsoon rains and sustained summer heat.

There are many more edible plants, flowers, berries, and mushrooms in the mountains. These are just 10 that can be easily identifiable and common in the Western Colorado landscapes. I recommend trying out the apps listed above and reading “Wild Edible Plants of Colorado” by Charles W. Kane, which includes 58 plants from various regions, each with details of use and preparation. Hopefully this post made you feel more prepared for your next adventure. 

Resources:

Davis, E., 2022. Fall plant tour: Frisco, CO | Wild Food Girl. [online] Wildfoodgirl.com. Available at: <https://wildfoodgirl.com/2012/eleven-edible-wild-plants-from-frisco-trailhead/> [Accessed 10 July 2022].

McGuire, P., 2022. 8 Delicious Foods to Forage in Colorado | Wild Berries…. [online] Uncovercolorado.com. Available at: <https://www.uncovercolorado.com/foraging-for-food-in-colorado/> [Accessed 10 July2022].

Rmhp.org. 2022. Edible Plants On The Western Slope | RMHP Blog. [online] Available at: <https://www.rmhp.org/blog/2020/march/foraging-for-edible-plants> [Accessed 10 July 2022].

Lifescapecolorado.com. 2022. [online] Available at: <https://lifescapecolorado.com/2014/01/edible-plants-of-colorado/> [Accessed 10 July 2022].

Pfaf.org. 2022. Plant Search Result. [online] Available at: <https://pfaf.org/user/DatabaseSearhResult.aspx> [Accessed 10 July 2022].

Cindy Hinh is a second-year Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up in southern Louisiana and received her undergraduate degree in Biology from Louisiana State University. Prior to PA school, she was a medical scribe in the emergency department and an urgent care tech. In her free time, she enjoys baking, cooking, going on food adventures, hiking, and spending time with family and friends.

Non-Freezing Cold Injury

Eighteen-year-old, NorAm skier, NCAA Division I Rugby player, and lover of the outdoors, presents to the clinic complaining of cold, painful hands. She states hands always feel cold, and in cold weather they are extremely painful. Blood tests to rule out vascular disease were normal. What could be the cause of this?

Normally, in cold weather our bodies work to keep essential organs functioning. Skin is not considered essential. When exposed to cold, blood vessels constrict, decreasing blood flow to the skin. Because the metabolic demand of our skin is low, more important organs like our heart and brain need the blood flow. Paradoxically, exposure to cooler temperatures like those below 15 degrees Celsius or 59 degrees Fahrenheit can cause cold-induced vasodilation. This allows blood to flow to the skin to help prevent more serious injury or frostbite. The vasodilation cycles in 5- to 10-minute intervals.

Nonfreezing cold injury (NFCI) occurs when tissues are damaged due to prolonged cooling exposure, but not freezing temperatures. NFCI is due to exposure of the extremities to temperatures around 0 to 15°C or 32 to 59°F, commonly the hands and feet. Current theory is that NFCI is due to a combination of vascular and neural dysfunction. With prolonged vasoconstriction, the skin experiences reduced blood flow with a neurological component influencing the damage as well.

Some patients living in cold environments like the Inuit, Sami people, and Nordic fisherman have a larger cold-induced vasodilation response and more rapid cycling. This is thought to decrease their risk of NFCI. Is it possible that patients who develop NFCI have a smaller and slower cycling of their cold-induced vasodilation? Could this be the issue with our patient with NFCI?  Further research is needed to learn more about NFCI and find better ways to treat it.

What we do know is there are 4 Stages of NFCI:

Stage 1: During the cold exposure – Loss of sensation, numbness, clumsiness. Usually painless unless rewarming is attempted.

Stage 2: Following cold exposure – occurs during and after rewarming. Skin can develop a mottled pale blue-like color, area continues to feel cold and numb, possible swelling. Usually lasts a few hours to several days.

Stage 3: Hyperemia – affected area becomes red and painful. Begins suddenly and lasts for several days to weeks.

Stage 4: Following hyperemia – affected areas appear normal but are hypersensitive to the cold. Areas may remain cold even after short exposure to the cold. This stage can last for weeks to years.

Mountains covered in pine forests reach up past tree line toward a deep blue sky spotted with fluffy white cumulous clouds over two people in bikinis standing on paddle boards reflected with the clouds in the dark water below them.

Outdoor paddle sports like kayaking and canoeing put patients at greatest risk due to the continual exposure to the cold, wet environment. It was thought that in order to have NFCI, one had to be exposed to both cold and wet environments. However, it has been shown that this is not always the case. Like in our patient, exposure to just cold environment can trigger the syndrome. Our 18-year-old patient is an avid skier and spends most of the winter on the mountain. It was also noted that she enjoys paddleboarding and kayaking, which were recognized as triggers for the hand pain. We are unable to determine exactly what caused our patient to develop this syndrome. But we do know it affects their life significantly.

 We choose to live in the mountains because of the things we love. Whether it is hiking, biking, skiing, kayaking, paddleboarding, or the hundreds of other activities offered in this area, we are at risk of NFCI. Currently, there is no good treatment for this syndrome. Prevention is  best. The purpose of this blog is to share information about staying healthy at high altitude. Sharing this information on the stages of NFCI with friends and family will help prevent this painful, debilitating syndrome.

Resources

Nonfreezing cold water (trench foot) and warm water immersion injuries. UpToDate. https://www.uptodate.com/contents/nonfreezing-cold-water-trench-foot-and-warm-water-immersion-injuries/print#:~:text=Nonfreezing%20cold%20injury%20%E2%80%94%20NFCI%20is,to%2059%C2%B0F)%20conditions. Accessed July 14, 2022.

Oakley B, Brown HL, Johnson N, Bainbridge C. Nonfreezing cold injury and cold intolerance in Paddlesport. Wilderness & Environmental Medicine. 2022;33(2):187-196. doi:10.1016/j.wem.2022.03.003

Rachel Cole is a Physician Assistant Student at Red Rocks Community College in Denver, Colorado. She originally grew up in Salt Lake City, Utah, where she learned to love the outdoors. She studied Biology at Western Colorado University in Gunnison, Colorado prior to PA school. She played soccer for the college and fell in love with Colorado and small mountain towns. When she is not studying for school, she enjoys skiing, hiking, backpacking, fishing, waterskiing, canyoneering, and any other activities that get her outside. After graduation she hopes to practice family medicine in a rural community in the mountains.

Beneficial Effects of Chronic Hypoxia

Living in Summit County, Colorado has its perks – residents are within a 20 to 40 minute drive to five world class ski resorts, and some of the most beautiful Rocky Mountain trail systems are accessible right out our back door. With the endless opportunities drawing residents outdoors to partake in physical activity, it comes as no surprise that Summit County is considered one of the healthiest communities in the country. However, there may be more than meets the eye when it comes to explaining this, as it also has something to do with the thin air.

As a Summit County native, you have likely heard the term “hypoxia” or “hypoxemia” mentioned a time or two. So what does this mean? Simply put, these words describe the physiological condition that occurs when there is a deficiency in the amount of oxygen in the blood, resulting in decreased oxygen supply to the body’s tissues. When this occurs in the acute setting, it may result in symptoms such as headache, fatigue, nausea, and vomiting. These are common symptoms experienced by those with altitude illness, also known as acute mountain sickness. While these symptoms can cause extreme discomfort and may put a huge damper on a mountain vacation, they are not usually life threatening. However, in a small number of people, development of more serious conditions such as a high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE) can occur. The treatment for all conditions related to altitude illness is oxygen, whether via return to lower elevations or by a portable oxygen concentrator that allows you to stay where you are. While altitude illness generally affects those who rapidly travel from sea level to our elevation, it has also been known to affect residents returning home to altitude, usually after a period of two or more weeks away. In a very small subset it can occur after a period of only a day or two. This generally occurs in those with a preexisting illness, where altitude exacerbates the condition.

While the acute effects of altitude can clearly have detrimental effects on one’s physical well-being, there is emerging research demonstrating that chronic hypoxia may actually come with several health benefits. Long time Summit County business owner and community pediatrician, Dr. Chris Ebert-Santos of Ebert Family Clinic in Frisco, has spent quite some time studying the effects of chronic high-altitude exposure, and recently attended and presented at the Chronic Hypoxia Symposium in La Paz, Bolivia, the highest capital city in the world.

It is important to first understand the adaptations that occur in our bodies as a result of long-term hypoxia. The ability to maintain oxygen balance is essential to our survival.

So how do those of us living in a place where each breath we take contains about ⅓ fewer oxygen molecules survive?

Simply put, we beef up our ability to transport oxygen throughout our body. To do this, our bodies, specifically the kidneys, lungs and brain increase their production of a hormone called erythropoietin, commonly known as EPO. This hormone signals the body to increase its production of red blood cells in the bone marrow. Red blood cells contain oxygen binding hemoglobin proteins that deliver oxygen to the body’s tissues. Thus, more red blood cells equal more oxygen-carrying capacity. In addition to increasing the ability to carry oxygen, our bodies also adapt on a cellular level by increasing the efficiency of energy-producing biochemical pathways, and by decreasing the use of oxygen consuming processes2. Furthermore, the response to chronic hypoxia stimulates the production of growth factors in the body that work to improve vascularization2, thus, increased ability for oxygenated blood to reach its destination. 

So, how can these things offer health benefit?

To start, it appears that adaptation to continuous hypoxia has cardio-protective effects, conferring defense against lethal myocardial injury caused by acute ischemia (lack of blood flow) and the subsequent injury caused by return of blood to the affected area3. The exact mechanism of how this occurs is not well understood, but it seems that heart tissue adapts to be better able to tolerate episodes of ischemia, making it more resistant to damage that could otherwise be done by decreased blood flow that occurs during what is commonly known as a heart attack. This same principle applied to ischemic brain damage when tested in rat subjects. Compared to their normoxic counterparts, rats pre-conditioned with hypoxia sustained less ischemic brain changes when subjected to carotid artery occlusion, suggesting neuroprotective effects of chronic hypoxia exposure4.

Additionally, it appears that altitude-adapted individuals may be better equipped to combat a pathological process known as endothelial dysfunction5. This process is a driving force in the development of atherosclerotic, coronary, and cerebrovascular artery disease. Altitude induces relative vasodilation of the body’s blood vessels compared to lowlanders2. A relaxing molecule known as nitric oxide, or NO, assists with causing this dilation, and in turn the resultant dilated blood vessels produce more of this compound5. The molecule has protective effects on the inner linings of blood vessels and helps to decrease the production of pro-inflammatory cytokines that damage the endothelium5. This damage is what kickstarts the cascade that leads to atherosclerosis in our arteries. Thus, a constant state of hypoxia-induced vasodilation may in fact decrease one’s risk of developing occlusive vascular disease. 

The topics mentioned above highlight a few of the proposed mechanisms by which chronic hypoxia may be beneficial to our health. However, do keep in mind that there are potential detrimental effects, including an increased incidence of pulmonary hypertension as well as exacerbation of preexisting conditions such as COPD, structural heart defects and sleep apnea, to name a few6. Research regarding the effects of chronic hypoxia on the human body is ongoing, and given its significance to those of us living at elevations of 9,000 feet and above, it is important to be aware of the impact our physical environment has on our health. Dr. Ebert-Santos is avidly involved in organizations dedicated to better understanding the health impacts of chronic hypoxia, and has several current research projects of her own that may help us to further understand the underlying science.

Kayla Gray is a medical student at Rocky Vista University in Parker, CO. She grew up in Breckenridge, CO, and spent her third year pediatric clinical rotation with Dr. Chris at Ebert Family Clinic. She plans to specialize in emergency medicine, and hopes to one day end up practicing again in a mountain community. She is an avid skier, backpacker, and traveler, and plans to incorporate global medicine into her future practice.

Citations

  1. Theodore, A. (2018). Oxygenation and mechanisms for hypoxemia. In G. Finlay (Ed.), UpToDate. Retrieved May 2, 2019, from https://www-uptodate-com.proxy.rvu.edu/ contents/oxygenation-and-mechanisms-of-hypoxemia?search=hypoxia&source=search_ result&selectedTitle=1~150&usage_type= default&display_rank=1#H467959
  2. Michiels C. (2004). Physiological and pathological responses to hypoxia. The American journal of pathology, 164(6), 1875–1882. doi:10.1016/S0002-9440(10)63747-9. Retrieved May 2, 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1615763/ 
  3. Kolar, F. (2019). Molecular mechanism underlying the cardioprotective effects conferred by adaptation to chronic continuous and intermittent hypoxia. 7th Chronic Hypoxia Symposium Abstracts. pg 4. Retrieved May 2, 2019. http://zuniv.net/symposium7/Abstracts7CHS.pdf
  4. Das, K., Biradar, M. (2019). Unilateral common carotid artery occlusion and brain histopathology in rats pre-conditioned with sub chronic hypoxia. 7th Chronic Hypoxia Symposium Abstracts. pg 5. Retrieved May 2, 2019. http://zuniv.net/symposium7/Abstracts7CHS.pdf
  5. Gerstein, W. (2019). Endothelial dysfunction at high altitude. 7th Chronic Hypoxia Symposium Abstracts. pg 11. Retrieved May 7, 2019. http://zuniv.net/symposium7/Abstracts7CHS.pdf
  6. Hypoxemia. Cleveland Clinic. Updated March 7, 2018. Retrieved May 9, 2019. https://my.clevelandclinic.org/health/diseases/17727-hypoxemia

Watch Out for Flying Discs: How High Altitude Changes Flight

by Laundon Transue, PA-S

Have you ever played disc golf? Maybe you know someone who has. Or maybe you’ve seen it from a distance. Perhaps you were taking a walk through a park or on a hiking trail and noticed a warning sign: “You Are Now Entering a Disc Golf Course – Watch Out for Flying Discs.” It can be a dangerous sport.

It’s just like golf, but with frisbees. Only instead of putting your ball into a hole in the ground, you throw your disc into an odd looking metal basket situated on top of a pole with a bunch of chains hanging from it. Maybe you’ve seen one such basket on your stroll through the park and thought “What is that thing?” That’s disc golf.

I learned to play this game in the forests and hills of Northern California, close to sea-level. Colorado is home to some of the best disc golf courses in the country, so I was excited to venture out and experience them after moving here. However, I could tell immediately that something was wrong the first time I played a round in Summit County – my discs were not flying like they used to!

How exactly were they flying differently? It was hard to say, I just knew they weren’t flying like I was expecting them to. It was throwing my game off. I’ve learned quickly that life at over 9,000 ft has all sorts of challenges not faced by sea-level dwellers. After a few rounds of disc golf up here and feeling like I had to learn how to play all over again, I wondered if my new high altitude environment had something to do with why my discs were misbehaving.

I set out to better understand the physics behind how discs fly through the air and how altitude affects these characteristics.

A lightweight flying disc traveling through the air is very sensitive to the atmosphere. At sea-level there is increased air density, so flying objects encounter more air resistance. As elevation increases, air density decreases, and there is less resistance in the air for flying objects to encounter. So yes, high altitude does cause flying objects to fly differently, but there’s a lot more to the story when it comes to disc golf.

Disc golf is a challenging game. The goal is to throw a ⅓ lb plastic disc hundreds of feet through the air across rough terrain while avoiding trees, hills, ponds, and eventually land in that odd metal basket, hopefully doing so in fewer throws than it takes your friends.

The fun part is throwing the disc far. Flying discs can travel much, much further than most other objects thrown by hand such as a baseball or football. The world record for throwing a golf disc stands at over 1,100 ft.

The hard part is throwing the disc accurately. Unlike a spherical object, the trajectory of a flying disc is not something easily graphed and calculated in your Physics 101 class. A ball thrown up in the air follows a relatively predictable parabolic path largely determined by the force of gravity acting on the sphere. It goes up, it comes down, easy-peasy.

The force of gravity also applies to a spinning disc as it flies. However, the unique shape of the disc, and the rotational torque (spin) acting on it, makes for a much more complex physics problem to solve. Disc golf is all about solving this physics problem in real time and in the real world.

As an object, such as a disc, flies through the air, it is constantly bumping into gas particles in the atmosphere which gradually slow the disc down until it eventually comes to a stop on the ground, this is wind (air) resistance. Also, the shape of a spinning disc thrown through the air generates lift, similar to the wings of an airplane. This means the air passing around the disc as it’s flying exerts an upward force which keeps the disc aloft longer, and this is why discs can be thrown so much further than a sphere. In summary, the air particles a disc encounters on its flight are responsible for both slowing down the disc due to air resistance, and for keeping the disc aloft due to lift. Fascinating!

Now here’s where it gets really complicated. You see, flying discs do not travel in a straight line. A disc thrown through the air will actually travel in an S-shaped line. If thrown by a right handed player, a disc will spin clockwise when viewed from above. When a disc leaves the golfer’s hand the clockwise spin will cause it to first start to drift to the right, then as the disc slows down it will start to drift back to the left, before finally landing on the ground. This property of flying discs to travel in an S-shaped line is termed stability.

Stability is a result of rotational torque and unequal air pressures generated on opposite sides of the disc. Think about the clockwise spinning disc described above. The left side of the disc (at the 9 o’clock position) is spinning into the wind, in the same vector as the trajectory of the disc. The right side of the disc (at the 3 o’clock position) is spinning away from the wind, in the opposite vector of the disc’s flight. This results in a high air pressure system on the left side of the disc, and a low air pressure system on the right side. Higher air pressure on the left means greater lift on the left. That unequal lift result is a gradual drifting of the disc to the right as it flies, and this is the first half of the S-shaped flight path caused by a disc’s stability.

To understand the second half of stability, we need to introduce another concept called gyroscopic precession. This is another complicated piece of physics, but it’s the same principle that keeps you from falling when riding on a hoverboard, and it’s what allows helicopters to maneuver around in the air. Gyroscopic precession says that if you apply a perpendicular force  to a spinning object, that force will be seen 90 degrees away in the direction of spin from where the force was applied. So if we have a clockwise spinning disc, and we apply an upward force at the 12 o’clock position, the disc will feel an upward force at the 3 o’clock position. Another example would be if we applied a downward force at the 7 o’clock position, then the disc would feel a downward force at the 10 o’clock position.

After the disc has traveled through the air for a bit it will start to slow down due to wind resistance. This means the disc will be moving at a slower velocity through the air, and will also be spinning at a slower rate. Slower speed through the air means less lift force acting on the disc and the disc will start to fall toward the ground. When the disc starts to fall, instead of the front of the disc slicing straight through the air like it did when it first left the golfer’s hand, the directional force of the air starts to push upward underneath the front of the disc. In other words, the disc is falling onto the air while it flies forward, and the air is now applying an upward force against the front of the disc.

So our disc is spinning clockwise, and now there is an upward force applied at the front of the disc (12 o’clock), then according to gyroscopic precession, the disc should feel an upward force at the 3 o’clock position (the right side of the disc). This upward force on the right side of the disc causes it to drift back toward the left until it eventually slows down to the point of landing on the ground.

Okay, that was a lot, let’s put it all together! A golf disc is thrown by a right handed player. The disc starts out flying through the air very fast and spinning at a high rate in a clockwise direction. The fast spinning disc creates higher pressure on the left side than the right due to air resistance. This left side pressure lifts and pushes the disc to the right as it’s flying. The disc starts to slow down and begins to fall, resulting in an upward force of air against the front of the disc. This upward air force produces a gyroscopic force 90 degrees away at the 3 o’clock position. The upward force on the right side of the disc causes it to fly back toward the left while the disc continues to slow and eventually lands on the ground.

Now that we know how discs are supposed to fly and how the atmospheric forces determine a disc’s flight, what changes should we expect to see when playing disc golf at high altitude?

At 9,000+ ft elevation there are significantly fewer gas particles in the atmosphere for discs to bump into during their flight. A disc will have less air resistance to deal with. That means it should fly faster and further, right? Not necessarily.

Remember, the atmosphere not only slows the disc down due to air resistance, it also provides the lift that keeps the disc up in the air for so long. Less gas particles in the atmosphere also mean less lift force.

So do discs fly shorter, further, or the same distance at high altitude? The answer is, it depends. Again, flying discs are a much more complicated physics problem than a flying baseball. Discs may fly further or shorter distances at high altitude compared to sea-level, but it depends on the type of disc, the player, and a whole host of other environmental factors such as specific elevation, temperature, humidity, and the direction of the wind.

What we can say, however, is that discs do fly differently at altitude. The shape of the S-path a disc takes at high altitude will look different due to the reduced air density, and this can spell trouble for a disc golfer who’s expecting their disc to turn right but instead it turns left.

During the first half of the stability S-curve, the disc is normally pushed toward the right due lift pressure created by air resistance. At high altitude less air resistance means less lift pressure generated during this first half of the S-curve, so the disc doesn’t move toward the right as much.

The second half of the S-curve is also changed. As we said before, less atmosphere mens less lift, so the disc will start to fall from its flight path sooner at high altitude. That means the upward air force on the front of the disc that results when it starts to fall will also occur sooner in the disc’s flight. Remember, this is the force that is felt by the disc 90 degrees away on the right side of the disc and pushes the disc to the left for the final part of its flight path.

At high altitudes discs drift less toward the right during the first half of their S-curve, and they begin the second half of their S-curve sooner along their flight path. The result is discs fly not so much in an S-shaped path, but rather a J-shaped, or hook-shaped path.

There you have it, High Altitude Disc Golf in a nut-shell. It was initially very frustrating when I started playing disc golf in Summit County. High altitude disc golf forces you to think about each hole and and each shot differently than you might at sea-level. The thin air changes the game dramatically, but that’s what I love most about disc golf. It’s a game that is virtually impossible to master, constantly challenges you, and can be enjoyed outside in the most beautiful and most extreme environments. Pick out a disc at your local sporting goods store and give it a try.

RSV: The Higher the Altitude, the Higher the Risk

Respiratory syncytial virus, RSV, is a common disease that predominantly affects infants and children throughout the world. Symptoms include mild fever, runny nose, coughing, and wheezing (CDC, 2021 and is the leading cause of bronchiolitis and pneumonia in children under the age of 1 in the United States. Because of this high risk of lower respiratory symptoms RSV is also the leading cause of hospitalizations within this age group (Sanofi Pasteur, 2021). Testing for RSV is quick and easy. Children under the age of 5 can be tested for RSV with a nasal swab and rRT-PCR test, similar to COVID-19 home tests (CDC, 2021) available at clinics and emergency rooms. . Unfortunately, preventing the spread of RSV and keeping these hospitalization rates to a minimum is more difficult at higher elevations.

One of our patients during admission after being diagnosed with RSV earlier in the day.

Higher elevations affect the body in many ways. The human body physiologically adapts within seconds of exposure to higher altitudes. Respiratory rate increases in order to compensate for the lower amount of oxygen circulating within the body (Scott, 2018). Within days to weeks, the body begins to acclimate to the higher altitude and this hypoxic state by maintaining this increased ventilation rate and increasing the amount of hemoglobin in the body (Scott, 2018). Due to the combination of effects on ventilation and oxygenation, managing respiratory infections like RSV becomes more difficult.

  The correlation between rates of RSV and higher altitudes has been studied more in recent years. It is hypothesized that the physiological changes that the body undergoes at higher altitude predisposes children to respiratory illnesses including RSV (Shi et al., 2015). In one study done in Colorado, the incidence of RSV within the population was higher than those at moderate and lower elevation areas. The rates of hospitalization increased 25% with children under the age of 1 and up to 53% with children between 1 and 4 (Choudhuri et al, 2006). Data shows that as altitude increases, the incidence of RSV increases, with elevations over 2500m considered as a modest predictor of RSV-related hospitalizations. The incidence of morbidity associated with RSV increases with higher elevation as well (Wu et al., 2015). This increased morbidity is attributed to the thick secretions that is caused by the virus. Since infants breathe through their nose until age 3, this collection of mucus causes respiratory issues including pauses in breathing with cyanosis called apnea. With studies showing the increased incidence, hospitalizations, and morbidity of RSV at higher altitudes, diagnoses of RSV should not be downplayed in children living at high altitudes.

Photo of the same patient as above on home oxygen after being discharged from the hospital.

It is important for providers and parents to be aware of the higher risk for more severe disease progression faced by children who reside at higher altitudes. Parents should recognize the symptoms of RSV and practice proper handwashing techniques to prevent the further spread of this disease within the community. Health care providers within these high-altitude areas should consider additional interventions and treatments such as home oxygen or nasal suctioning which may be beneficial to preventing hospitalizations due to RSV. Dr. Chris advises parents with older children in daycare or preschool to consider keeping them home during RSV season (November-April) when they have a new baby in the house. Although it is imperative to properly diagnose and treat RSV to avoid hospitalizations, obtaining a chest x-ray and treating with medications like albuterol or steroids is unnecessary. Ultimately, although RSV is a benign disease to most, in areas of higher elevation, it must be taken seriously order to prevent unfavorable outcomes.

References

Centers for Disease Control and Prevention. (2021, September 24). Symptoms and care of RSV (respiratory syncytial virus). Centers for Disease Control and Prevention. Retrieved April 28, 2022, from https://www.cdc.gov/rsv/about/symptoms.html 

Choudhuri, J. A., Ogden, L. G., Ruttenber, A. J., Thomas, D. S., Todd, J. K., & Simoes, E. A. (2006). Effect of altitude on hospitalizations for respiratory syncytial virus infection. Pediatrics, 117(2), 349–356. https://doi.org/10.1542/peds.2004-2795

Sanofi Pasteur. (2021). Rethink RSV. Retrieved April 28, 2022, from https://www.rethinkrsv.com/

Scott, B. (2018, June 13). How does altitude affect the body? Murdoch University. Retrieved April 28, 2022, from https://www.murdoch.edu.au/news/articles/opinion-how-does-altitude-affect-the-body#:~:text=Many%20people%20who%20ascend%20to,lethargy%2C%20dizziness%20and%20disturbed%20sleep 

 Shi, T., Balsells, E., Wastnedge, E., Singleton, R., Rasmussen, Z. A., Zar, H. J., Rath, B. A., Madhi, S. A., Campbell, S., Vaccari, L. C., Bulkow, L. R., Thomas, E. D., Barnett, W., Hoppe, C., Campbell, H., & Nair, H. (2015). Risk factors for respiratory syncytial virus associated with acute lower respiratory infection in children under five years: Systematic review and meta-analysis. Journal of iglobal health, 5(2), 020416. https://doi.org/10.7189/jogh.05.020416

Wu, A., Budge, P. J., Williams, J., Griffin, M. R., Edwards, K. M., Johnson, M., Zhu, Y., Hartinger, S., Verastegui, H., Gil, A. I., Lanata, C. F., & Grijalva, C. G. (2015). Incidence and Risk Factors for Respiratory Syncytial Virus and Human Metapneumovirus Infections among Children in the Remote Highlands of Peru. PloS one, 10(6), e0130233. https://doi.org/10.1371/journal.pone.0130233

Claire Marasigan is a 2nd year PA student currently studying at Midwestern University in Glendale, Arizona. Claire has lived her entire life in Arizona and went to Grand Canyon University for her undergraduate degree in Biology. Prior to PA school, she was a medical scribe trainer at St. Joseph’s Hospital in Phoenix. In her free time, she loves to cook, try new restaurants with friends, and play with her dog, Koji.